Protect Natural Gas Sample Integrity and Prevent Sulfur Loss with Sulfinert® Sample Cylinders

Importance of the Topic

Natural gas streams often contain sulfur species such as hydrogen sulfide, mercaptans and thiophenes that can corrode equipment, poison catalysts and reduce heating value. Preserving the integrity of these reactive analytes from sampling through analysis is essential for accurate quantification and safe, efficient downstream operations.

Objectives and Study Overview

This work evaluated Sulfinert®-passivated sample cylinders against standard stainless steel cylinders to determine their effectiveness in preventing sulfur adsorption. Simultaneous gas samples were collected and monitored over a multi-day period to compare stability of key sulfur compounds.

Methodology and Instrumentation

At the point of use, 1 L cylinders—one untreated stainless steel and one Sulfinert®-treated—were filled under identical conditions. Samples were analyzed by gas chromatography using an Rtx®-1 column and a sulfur chemiluminescence detector. Dimethyl sulfide served as an internal standard to track losses of ethyl mercaptan over time.

• Gas chromatograph: HP5890 GC
• Column: Rtx-1, 60 m × 0.53 mm ID, 7 µm film
• Detector: Sievers 355 Sulfur Chemiluminescence Detector at 800 °C
• Carrier gas: Helium, constant pressure, 96 cm/s at 30 °C
• Oven program: 30 °C (1 min) → 100 °C at 30 °C/min (hold 60 min)
• Injection: direct at 30 °C

Key Results and Discussion

Initial analyses (30 min post-collection) showed similar sulfur levels in both cylinders. By 24 h, the untreated cylinder had lost 34 % of ethyl mercaptan and 56 % by Day 4, whereas the Sulfinert® cylinder lost only 6 % over the same interval. By Day 16, reactive mercaptans were undetectable in the stainless steel cylinder but remained quantifiable in the Sulfinert® cylinder, demonstrating its superior inertness.

Benefits and Practical Applications

Sulfinert®-passivated cylinders minimize adsorption of highly reactive sulfur species, ensuring that analytical results accurately reflect the true composition of natural gas samples. This enhances quality control in petrochemical processes, supports compliance with fuel specifications and protects sensitive equipment.

Future Trends and Opportunities

With increasingly stringent sulfur specifications and diverse gas sources, demand for ultra-inert sampling technologies will rise. Future developments may include customized surface treatments for a wider range of analytes, integrated real-time sampling and analysis platforms, and portable devices for on-site monitoring.

Conclusion

Applying Sulfinert® passivation to sampling cylinders significantly improves the stability of sulfur compounds in natural gas, enabling accurate long-term storage and analysis that reflect true sample composition.